US2181854A

US2181854A - Refrigeration apparatus and method

Info

Publication number: US2181854A
Application number: US156162A
Authority: US
Inventors: William B Anderson; Graham S Mccloy
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1937-07-28
Filing date: 1937-07-28
Publication date: 1939-11-28
Anticipated expiration: 1956-11-28

Description

Nov. 28, 1939. w. B. ANDERSON ET AL 2,181,854

REFRIGERATIQN APPARATUS AND METHOD Filed July 28, 1937 THEM WY 5C. F-RL Y O TDC WA m wa m wmunn GPRBHAM I9 WITNESSES:

Patented Nov. 28, 1939 UNITED STAT ES PATENT OFFICE REFRIGERATION APPARATUS AND METHOD A l at Jul .2 1 37. Se a P- 6.1 2

21 Cl ims- Our invention relates to refrigeration apparatus .and to a method for charging refrigeration apparatus with refrigerant and lubricant.

Beforea closed refrigerating system is charged, it is necessary for several reasons to remove all non-condensable gases, such as, for example, air, -from the refrigeratingsystem. For example, the presence of non-condensable gases will cause high head pressures in thehigh side of the system -so that the efficiency of the system willbe reduced and, if large amounts of non-condensable gases are present the machine may cease to operate. Furthermore, non-condensable gases and air in the system may cause oxidationand deterioration of the parts of the system. Again,=in refrigerating systems where lubricant is present, the noncondensable gases and air sometimes react with the lubricant or refrigerant and form water, with the result -;that the water combines with other chemicals in the system and causesoxidation and rusting of the parts of the refrigerator. Inhermetically sealed systems wherein the motor and compressorare contained withina sealed casing, the presence of non-condensable gases or air may form chemical combinations with the refrigerant and lubricant which deleteriously effect-the insulation on the windings of the motor etc. Itis, therefore, necessary "to completely evacuate all non-condensable gases from the system before it gisplaced in the field charged with-liquid refriger- :ant and lubricant.

Heretofore, refrigerating systems have been charged ,withliquid refrigerant by first drying the refrigerating system with Warm air or inert gas and then evacuating the system with high vacuum apparatus. The apparatus for performing the evacuation portion of the process is expensive, cumbersome, and necessarily slow in operation and, furthermore, it is very difiicult to completely remove the non-condensable gases from the system. In addition, the refrigerant and lubricant with which the system is afterwards chargedcontain'non-condensable gases which are not removed .by priorevacuation.

-It'is an object of our invention, therefore, to a provide improved apparatus and an improved method for removing non-condensable gases from a refrigerating system and for charging the system with refrigerant.

It is also an object of our-invention to remove the non-condensable gases from the system by operation of the compressor of'the refrigerating .systemand to thus dispense withexpensive and cumbersome evacuating apparatus.

Itis,still -afurthercbject of our invention'to tube.

provide evacuating and charging apparatus which may be readily used in the field for servicing refrigerating systems.

It is still another object of our invention to provide an evacuatingand chargingsystem for refrigerating units which is particularly adaptable-for use in systems in which a hermetically sealed motor compressor unitis utilized.

It is another object of our invention to provide a method of evacuating and charging a refrigerating system wherein the non-condensable gases which are contained inthe refrigerant and lubricant charge are removed from the system.

It is still another object of our invention to provide apparatus for charging a refrigerating M system with refrigerant which readily adapts itself to accurately charging therefrigerantbythe weight thereof, which is considerably more accurate than charging by volume.

It is also an object of ourinvention toprovide a charging system which'is particularly adapted to large production methods and which may beused to evacuate and charge the refrigerating systems without removalfrom a moving conveyer assembly and test system and without stopping the conveyer.

These and ,other objects are effected by our invention, as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. l of thedrawing is a diagrammatic illustrationtof a-refrigerating system embodyingour invention; and

Fig. 2 is a view of a system similar to that shown in Fig. 1,-but using a float valve flow restrictor instead of a capillary tubebetween .thecondenser and the evaporator.

Referring specifically to the drawing for a .detailed descriptionof our invention, humeral ll designates a sealed casing in which iscontaineda reciprocating compressor l2 and a drivingmotor i3. Refrigerant is forced from the compressor l2 through a conduit M in a high pressure and superheated gaseous state to a condenser l 5. The high pressure refrigerantgas is cooled in the condenser and condensed, a motor-driven fan i6 forcing cool air over the, condenserfor that purpose. In the system shownin Fig. 1, condensed refrigerant is conveyed through a conduit H to.a

tube i 8 of considerable length and restricted diameter sometimes referred to as a capillary The capillary tube l8 feeds refrigerant into an evaporator i9 inwhich therefrigerantis vaporized and isdrawn into theinteriorofthe sealed casing I through a conduit 2! Low pressure refrigerant vapor in the casing is drawn into the compressor through an inlet conduit 22 and the cycle is then repeated. It is, therefore, apparent that the interior of the sealed casing and the motor windings are subjected to the low pressure refrigerant gas.

In accordance with our invention as shown in Fig. 1, a combination purge valve and charging valve 23 is disposed in the conduit I4 extending between the compressor and the condenser. A threaded opening 24 in the valve 23 receives a threaded plug 25 which may be removed for purging the system. The valve 23 is provided with a standpipe 26 attached to an opening 2! in the valve by soldering or brazing. The upper end of the standpipe 26 is threaded as indicated at 28. An assembly consisting of a hand operated valve 29 and a closed container 3| communicating with the valve 29 is attachable to the threaded opening 28 by a threaded conduit 32 and a connecting fitting 30. i The refrigerating system is first subjected t a flow of warm dry air or inert gas, such as, for example, nitrogen, for a sufficient time to substantially remove the moisture from the system. After dehydration, the system, still filled with air or inert gas is placed on a conveyer (not shown) and is charged with the proper amount of lubricant through a conduit 20, which opens into the motor-compressor casing and which is pinched off and sealed after lubricant charging. During this time, the system is open to the atmosphere through the conduit 2%) and through the standpipe 26, since the hand valve 29 and container 3! have not as yet been attached. The entire system is, however, above room temperature, having been heated by the warm drying gas, and very little, if any, air from outside the system will enter it.

At this time, the pressure throughout the system is substantially at atmospheric pressure. After the system has been charged with lubricant and the pipe 20 pinched off, the compressor is preferably operated for a short time, such as two minutes, with the result that partial evacuation of the low side of the system is effected. This operation is also known as auto-evacuation since it is effected by the operation of the system itself. The air or gas present in the low side of the system comprising mainly the evaporator i 9 and the interior of the sealed casing I! is exhausted to the atmosphere, for example, through the open end 28 of the standpipe 26. The pressure in the low side of the system is thus reduced to 25 inches of vacuum or lower. The pressure in the high side of the system, comprising mainly the condenser I5 and conduits I 4 and I1, is still at atmospheric pressure because it is vented to the atmosphere through the open standpipe 26.

The high pressure side of the system is closed to atmosphere while the compressor is still operating. In the capillary tube type of refrigerating apparatus illustrated in Fig. l, the screw fitting 30 is attached to the threaded ends of the standpipe 26 and conduit 32 while the compressor is still operating. Liquid refrigerant sufficient to charge the system is present in the container, and the hand valve is closed. This procedure is followed because if the compressor were stopped, air would again-quickly leak into the low side of the system and negative the effect of the autoevacuation which has just been completed. The pressure in the high side does not build up to any appreciable extent at this time because the low .side is substantially evacuated and only small at this time.

quantities of gas are being pumped into the high side of the system. At this time, the exact refrigerant charge b weight is within the container 3!. While most of the refrigerant by weight is in liquidstate in the container 3!, some refrigerant gas is present in the container 3!. Most'refrigera'nts, 'such as sulphur dioxide or dichlorodifiuoromethane, are at a higher pressure than atmospheric in the container 3! when subject to room temperatures. However, it is not necessary for successful utilization of our invention that the refrigerant pressurein the container 3! be above atmospheric After the hand valve 29 and the refrigerant filled container 3! are attached to the standpipe 26, the compressor !2 is stopped by deenergizing the motor !3. The hand valve 29 is then opened and: liquid refrigerant runs into the system by gravity, or by pressure difference and gravity if the pressure in the container 3! is above the'rires sure in the high side of the refrigerating systhrough hand valve 28, conduit 32 and standpipe 26, by gravity. The conduit 32 and standpipe 26 are of sufiicient diameter that the condensed refrigerant on the one hand and the gaseous refrigerant and non-condensable gases on the other hand flow therethrough in counter-flow relation. The non-condensable gases delivered to the container 3! are not condensed and remain therein until, within a relatively short time, all the non-condensable gases remaining in the system after auto-evacuation are contained in the container 3!, together with a small quantity of re-- frigerant gas. The hand valve 29 is then closed and the standpipe 26 is pinched ofi" and immediately sealed. The hand valve 29 is then unscrewed from the threaded connection on the standpipe, and the hand valve 29 and container- 3! are used on another refrigerating system for charging the same.

By first auto-evacuating the system of noncondensable gases, the size of the container 3! may be relatively small, it being sufficiently large,

however, to contain the exact refrigerant charge required for the system. It will also be apparent that the container 3! is preferably disposed above the highest liquid level of the system, sinceit is connected into the high side of the system and it 3 is desirable that condensed liquid refrigerant from the container 3! return to the system by gravity when the compressor 2 is operating. The complete evacuating and charging operation may be started and completed as soon as the system has been dried, and the system need not be removed from the conveyer atany time. The size of the container .3! maybe considerably'less than the sealed casing and obviously does not occupy much space above the conduit l4.v

In the embodiment of our invention shown in V Fig. 1, utilizing a capillary tube, non-condensable denser, and the container 3! is, therefore, jconinected intothecconduit I4; In the embodiment :shown in :Fig.i2,;however, a refrigerating-system utilizinga float valve 3.5.controls the flow of refrigerant :from the high to the low side of the system. Like numerals designate the parts of compression system in -Fig. 2 as in Fig. 1 with the exception of the float valve and the parts of ithe system used for charging, The float valve .135 :comprises a tank 36 into which liquid refrigerant from the condenser I5 is discharged through :conduit .31. A float ball 38 is hingedly .supportedrat 40 within the tank 35 and operates .a .valver39 including a needle plunger 4| which .coacts with a .valve seat 42. therefore, opened and closed in response to .c-hangesin liquid level in the tank 36. The tank :i'36.is also provided with a purge opening 43 closed .bya threaded plug 44.

Since non-condensable gases collect in the top of zthe float tank 36, in this embodiment of our invention, a container 45 for charging the system is connected to the .top of the float tank 36 by a standpipe 45 welded or brazed to an opening 41in the'top of thefioat tank. The standpipe 46 is provided with a threaded upper end 48 to which a threaded conduit 49 is attached by a fitting 5|. The conduit 49 isconnected to a hand valve 52 whichconnects the float tank 35 with the container 45, when it is open. The container 45 is disposed above the highest liquid level in the system, since it is also desirable in this embodiment of our invention to have the refrigerant liquid runinto thesystem by gravity when the compressor (not shown) is operating.

The system-shown-in-Fig. 2 is dried and charged with liquid refrigerant by the same steps and in the-same sequence-described with respect to Fig. 1. Clearly, as the liquidrefrigerant charge flows into the system, and as refrigerantgas is con- =densed, liquid refrigerant enters the float tank -36 and lifts the valve 39 so that the charge "is properly distributed throughout the system.

Asthecompressor I2operates, a mixture of refrigerant gas and non-condensable gases are forced into -'the container 45, whereupon the "refrigerant gas condenses and returns to the-syste'm through handvalve'52, conduit 49 and standpipe'45, while the non-condensable gases remain in the container 45. After all the non-condensable gases are-contained within the container 45,

and the system has been charged, the standpipe' 46 is pinched off and immediately sealed and the hand valve 52 and container 45 may be used on another system. I

The method of removing the-non-condensable gases'from a system'which contains its refrigerant 'andlubricant charge is fully-disclosed and claimed in'the copencling application of Graham S. McCloy,'Serial No. 140,011, filed April 30, 1937, "andassigned to the'assignee of the present ap plication.

From the foregoing, it willbe apparent-that we have provided animproved system and method ffo-r charging refrigerating units with refrigerant and lubricant, which system and method dispenses with expensive evacuating apparatus and is also adaptable for use in either the factory or in the field. While we have shown 'our inven- 'tion as applied to a-khermeticallysealed compression refrigerating unit, itis obvious-that our invention is applicable to many otheriforms of re frigerating systems.

While we have shown our invention in two forms,'it-wi1l 'beobvious to .thosezskilled'in the art that it is not so limited, butis susceptible of The valve 39 is,

various other changes and modifications without departing from the spirit thereof, and we desire,

therefore, :that only such limitations shall be :placed thereupon as are imposed by the prior .art .or .as are specifically set forth in the appended claims.

What we claim is: :1. The method of charging a closed refrigeratingsystem with a refrigerant, which system'in- Icludes a compressor and initially contains gases whichare non-condensable at ordinary temperatures, which method comprises connecting a containeriof refrigerant into the system, the quantity of refrigerant in said container at the time of connecting it being sufiicient for charging the system, {operating the compressor to'force said non-condensable gases into said container and transferring said refrigerant from said container intothe system.

2. The method of charging a closed refrigerate ing system with a refrigerant, which system includesa compressor and initially contains. gases .whichare non-condensable at ordinary temperatures, which method comprises connecting a container in communication with the high pres- ,sure side of the system, supplying the container with a charge of refrigerant most of which, by weight, is in liquid state, and which is sufficient for a complete charge for the system, transferring liquid refrigerant from the container into.

the system, operating the compressor to force the non-condensable gases into the container, condensing gaseous refrigerant which enters the container from the system as the compressor operates,,retaining the non-condensable gases in. r

the container, continuing the operation of the compressor until the system is completely charged with refrigerant and substantially all the noncondensable gases are in the container and then isolating the system from said container.

3. The method claimed in claim 2 wherein the container is removed from the system and the v.systemis sealed when substantially all the non- .condensable gases have been transferred to the of refrigerant between the condenser and the :evaporator and which system initially contains gases which are non-condensable at ordinary temperatures, which method comprises connect- ,ing a container in communication with the high pressure side of the system, supplying the con- ,tainer with a charge of refrigerant most of which. :by weight, is in liquid state, and which is sufficient for a complete charge for the system,

transferring liquid refrigerant into the system,

operating the compressor to force the non-con- ,densable gases into the container, condensing gaseous refrigerant which enters the container from the system'as the compressor operates, reftaining the non-condensable gases in the container, continuing the operation of the compressor until the system is completely charged with refrigerant and substantially all the non-con- .densable gases are in the container and then isolating thesystem from said container.

5. The method of charging a closed refrigeratiim systemhaving high and low pressure sides with arefrigerant, said system including a motorcompressor unit which is enclosed by ahermetically-sealed casing normally containing refrigerant :gas and-which system initially contains gases Gil stantially all the non-condensable gases are in the,

container.

6. The method of charging a closed refrigerating system with refrigerant, said system including a compressor and initially containing gaseswhich are non-condensable at ordinary temperatures and which system is divided into high and low pressure sides, which method comprises operating the compressor with the high pressure side open to the atmosphere to substantially exhaust the non-condensable gases fro-m the low pressure side, connecting a container in communication with the high pressure side of the system, supplying the container with a charge of refrigerant, transferring refrigerant into the system, operating the compressor to force the non-condensable gases into the container, condensing gaseous refrigerant which enters the container from the system as the compressor operates, retaining the noncondensable gases in the container, continuing the operation of the compressor until the system is completely charged with refrigerant and substantially all the non-condensable gases are in the container and then isolating the system from said container.

7. The method of charging a closed refrigerating system with a refrigerant, which system includes a compressor and initially contains gases which are non-condensable at ordinary temperatures, and which system is divided into high and low pressure sides by a float controlled valve, which method comprises operating the compressor with the high pressure side of the system open to atmosphere to substantially exhaust the non-condensable gases from the low pressure side of the system, connecting a container in communication with the high pressure side of the system and disposing it above the portion of the system to which it is connected, supplying the container with a charge of refrigerant most of which is in the liquid state, transferring liquid refrigerant into the system, operating the compressor to force the non-condensable gases into the container, condensing gaseous refrigerant which enters the container fromthe system as the compressor operates, retaining the non-condensable gases in the container, continuing the operation of the compressor until the system is completely charged with refrigerant and substantially all the non-condensable gases are in the container and then isolating the system from said container.

8. In refrigerating apparatus in which a refrigerant is compressed, condensed and vaporized, the combination of a compressor, a condenser, an evaporator, a device for controlling the flow of refrigerant between the condenser and the evaporator, said compressor and condenser embodying a high pressure side of the system and said evaporator embodying a low pressure side of the system, and a container containing a complete charge of refrigerant for the system adapted to be connected to the high pressure side of the system and so' disposed thatlrefrigerant will be transferred into the system, said container being adapted to collect the non-condensable gases present in the system and to retain the noncondensable gases therein.

9. In a refrigerating system in which a refrigerant is compressed, condensed and vaporized, the combination with a compressor, a condenser, an evaporator, a flow control device of relatively-restricted diameter and considerable length disposed between the condenser and the evaporator, aconduit connecting the condenser with the compressor and container connected into and disposed above highest liquid level in the system,

said container containing a complete charge of refrigerant for the refrigerating system so that the refrigerant will flow into the system, said container being adapted to collect the non-condensable gases present in the system when said compressor is operating and to retain the noncondensable gases therein.

10. In refrigerating apparatus in which a refrigerant is compressed, condensed and vaporized, the combination with a compressor, a condenser, an evaporator, a float controlled device disposed between the condenser and the evaporator, a container connected to said float control device'in the high pressure portion thereof, said container containing a complete charge of refrigerant for the refrigerating system so that therefrigerant will flow into the system, said container being adapted to collect the non -condensable gases present in the system when said compressor is operating and to retain the non-condensable gases therein.

11. The method of effecting the exchange of refrigerant and non-condensable gases between .a container and a refrigerating system having refrigerating system, establishing communication between the container andthe refrigerating system and effecting the delivery of the refrigerant in the container to the refrigerating system, operating the compressor for circulating refrigerant and the non-condensable gases in .the refrigerating system, collecting the non-condensable gases in the container and terminating communication between the container and the refrigerating system when substantially all of the noncondensable gases and refrigerant have been exchanged.

12. The method of charging and removing non-cond-ensable gases from a refrigeratingsystem having high and low pressure sides and including an evaporator, a compressor, a condenser, and an expansion device, which method comprises admitting to a container sufiicient refrigerant for a complete refrigerant charge for the system, connecting the container with the refrigerant charge therein to the high-pressure side of the system, transferring the refrigerant charge from 'the container to the system, and transferring from the system to the container those non-condensable gases which are contained in the system at the time of transfer of the refrigerant charge into the system by operating the compressor to effect flow of a mixture of non-condensable gases and refrigerant vapor at substantially condenser pressure into the container, and condensing refrigerant vapor in'the container and returning the condensed refrigerant to'the system; I

13;. The method of: charging and removing;

non-condensable: gases. from, a refrigerating system including an evaporator, a compressor, a condenser, and anexpa'nsion device, which meth d: comprises. connecting a. container containing refrigerant to' thev high pressure side of the. system, transferring? refrigerant: from the container to': the system, collecting. in the container substantially" all the.- nonrcondensable gases containect in: the: system atthe, time. of transfer of refrigerant into the system by operating the compressor: to. effect"v flow of? a mixture of noncondensable. gasessand. refrigerant vapor at condenser pressure into the container and condensing refrigerant vapor in the container, the refrigerant condensed in the container being returned to the system, and then disconnecting the container from the system.

14. The method of charging and removing non-condensabie gases from a refrigerating system, which method comprises admitting to a container only the quantity of refrigerant required for a complete refrigerant charge for the sys tem, connecting the container with the refrigerant charge therein to the system, transferring the refrigerant charge from the container to the system, and transferring the non-condensable gases from the system to the container byoperating the system to effect flow of a mixture of non-condensable gases and refrigerant vapor into the container.

15. The method of charging and removing non-condensable gases from a refrigerating system including an evaporator, a compressor, a condenser, and an expansion device, which method comprises admitting to a container the proper amount only of refrigerant required for a complete refrigerant charge for the system, connecting the container with the refrigerant charge therein to the high pressure side of the system and transferring the refrigerant charge to the system, and removing from the system the'noncondensable gases contained therein at the time of transferring the refrigerant charge to the system by operating the compressor to effect flow of a mixture of non-condensable gases and re frigerant vapor at condenser pressure into a heat transfer device and condensing refrigerant vapor therein, the refrigerant condensed in the heat transfer device being returned to the system, and closing communication between the system and the container.

16. The method of charging and removing non-condensable gases from a refrigerating system including an evaporator, a compressor, a condenser, and an expansion device of a type which passes some gaseous fluid under some conditions of operation, which method comprises admitting to a container sufiicient refrigerant for a complete refrigerant charge for the system, connecting the container with the refrigerant charge therein to the high pressure side of the system between the compressor discharge and the condenser inlet, transferring the refrigerant charge from the container to the system, transferring from the system to the container the non-condensable gases contained in the system at the time of transfer of the refrigerant charge into the system by operating the compressor to effect flow of a mixture of non-condensable gases and refrigerant vapor at condenser pressure into the container and condensing refrigerant vapor in the container, the refrigerant condensed in the container being returned to the system.

17. The method of charging and removing nonecondensablegases, from; a refrigerating system. including; an; evaporator, a compressor, a;

condenser,. and: an expansion device, said. 7 expansion: device receiving only liquid refrigerant: in: the normal operation of the therefrigerant. charge; from the container to the.

system, removing from the system the non-condensable gases contained therein at the time of transferring the refrigerant charge into the system by operating a compressor to effect flow of a mixture of non-condensable gases and refrigerant vapor at condenser pressure into the container and condensing refrigerant vapor in the container, the refrigerant condensed in the coin tainer being returned to the system, and then isolating the non-condensable gases in the container from the refrigerant charge in the system.

18. The method of charging and removing non-condensable gases from a refrigerating system including a compressor, which method comprises operating the compressor to exhaust a substantial quantity of non-condensable gases from the low-pressure side of the system to the highpressure side and venting non-condensable gases from the high-pressure side, admitting a refrigerant charge to the system, providing a container connected to the system, transferring from the system to the container the non-condensable gases contained in the system at the time of admitting the refrigerant charge thereto by operating the compressor to effect flow of a mixture of non-condensable gases and refrigerant vapor into the container and condensing refrigerant vapor in the container, and returning the refrigerant condensed in the container to the system.

19. The method of charging and removing non-condensable gases from a refrigerating system including a compressor, which method comprises operating the compressor to exhaust a substantial quantity of non-condensable gases from the low-pressure side of the system to the highpressure side and venting non-condensable gases from the high-pressure side, admitting a refrigerant charge to the system, providing a container connected to the high-pressure side of the system, transferring from the system to the container the non-condensable gases contained in the system at the time of admitting the refrigerant charge thereto by operating the compressor to effect flow of a mixture of non-condensable gases and refrigerant vapor at substantially condenser pressure into the container and condensing refrigerant vapor in the container, the refrigerant condensed in the container being returned to the system, and isolating the non-condensable gases in the container from the refrigerant charge in the system.

20. The method of charging and removing noncondensable gases from a refrigerating system including a compressor, which method comprises operating the compressor with the high pressure side of the system open to the atmosphere to substantially exhaust the non-condensable gases from the low pressure side of the system, admitting to a container the proper amount only of refrigerant required for a complete refrigerant 21. The method of charging and removing non-condensable gases from a refrigerating system including an evaporator, a compressor, a condenser, and an expansion device, which method comprises connecting to. the system a container containing refrigerant for charging the system, transferring refrigerant from the container to the system, transferring non-con densable gases from the system to the container by operating the compressor toeifect flow of a mixture of non-condensable gases and refrigerant vapor into the container,.condensing refrigerant vapor in the container,- and returning the refrigerant condensed in the container to the system. V 1

- WILLIAM B. ANDERSON.

GRAHAM S. MCCLOY.